Diesel engine

A diesel engine comprises a high-pressure pump (5) driven by an engine (E) to supply fuel in a fuel tank (2) to a common rail (3), an electric priming pump (13) provided in a fuel passage (15) extending from the fuel tank (2) to the high-pressure pump (5), and a control device (10) to control the electric priming pump (13). The control device (10) drives the electric priming pump (13) when the engine is started, if a state that the engine rotating speed (Ne) is higher than a predetermined first rotating speed (N1) and the common rail pressure (Cp) is lower than a predetermined first pressure (C1) continues for a period being equal to or more than a predetermined first period (T1). The burden on the operator is mitigated since necessity for the priming operation can be automatically judged.